1. Field of the Invention
The present invention is broadly directed to a locking assembly for fastening two components together and, more particularly, to an improved fluid coupling assembly for providing a compression sealed joint that can maintain its preload characteristics.
2. Description of Related Art
Numerous apparatuses have been utilized to retain the mechanical coupling of two component parts during use. As is well known, application of stress, vibration, and movement to a structure can frequently cause a loosening and release of a desired seating torque between a pair of components. A traditional method of attaching two component parts is to provide respective threads in a nut and bolt arrangement, and to preload or torque the components to a desired compression. Numerous methods have been suggested to inhibit the subsequent loosening of such a structure. Thus, lock washers, serrated surfaces, interference thread fitting, tapered threading surfaces for providing interference, nut plates, and lock wiring have been used. Adhesive materials have also been used as thread sealers to lock the two components together.
A particular problem can occur in pneumatic and hydraulic connectors that may not only be subjected to external vibrations and stresses, but also pressure stresses from the fluid that is being conducted through the sealed joint. In the aircraft industry, a substantial number of fluid coupling joints consist of compression fittings that are secured together by a nut which is subsequently lock wired to a mating coupling component in such a manner that the nut cannot turn with respect to the fitting to ensure against any loss of fluid tightness in the sealing joint. Fluid coupling joints are frequently located in areas where vision can be obscured, and the assembling of the joints must be made out of the direct vision of the worker. In such events, lock wiring is an unsatisfactory means of securing the joint against subsequent loosening. As can also be appreciated, inspection of the joint to ensure its integrity is often compromised.
An example of a lock wire fluid coupling can be found in U.S. Pat. No. 3,702,707. An alternative hydraulic connector can be seen in U.S. Pat. No. 4,877,271, wherein a lock ring can be engaged by a friction fit between the two component parts to secure the coupling.
There is still a need in the fastening arts to provide a coupling system having a retention mechanism that is activated by the same movement for creating the compression seal between the parts and does not require a secondary activity to effectuate the safety joining and retention of the component parts. Additionally, there is a further need to enable a verification of an effective operation of the retention mechanism independent of visual observation.